
/** 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package com.tompai.datagather.util;

import java.io.File;
import java.util.concurrent.atomic.AtomicInteger;
/**
* @author: tompai
* @createTime: 2018年4月28日 下午7:42:41
* @history:
* @version: v1.0
*/
public class FileIdGenerator {
    protected File baseDir;
    protected AtomicInteger lastId;

    public void initLastId(){
        lastId = new AtomicInteger(-1);
        if(baseDir.exists()){
            for(File file:baseDir.listFiles()){
                int id = Integer.valueOf(file.getName().split("\\.")[0]);
                if(id > lastId.get()){
                    lastId.set(id);
                }
            }
        }
    }

    public int generate(){
        return lastId.incrementAndGet();
    }

    public FileIdGenerator(File baseDir) {
        this.baseDir = baseDir;
        initLastId();

    }
    public FileIdGenerator(String baseDirPath){
        this(new File(baseDirPath));
    }

    public static void main(String[] args) {
        FileIdGenerator generator = new FileIdGenerator("test");
        for(int i=0;i<100;i++){
            System.out.println(generator.generate());
        }
    }
}
